Causal Boxes: Quantum Information-Processing Systems Closed under Composition

Complex information-processing systems, for example quantum circuits, cryptographic protocols, or multi-player games, are naturally described as networks composed of more basic information-processing systems. A modular analysis of such systems requires a mathematical model of systems that is closed under composition, i.e., a network of these objects is again an object of the same type. We propose such a model and call the corresponding systems causal boxes. Causal boxes capture superpositions of causal structures, e.g., messages sent by a causal box A can be in a superposition of different orders or in a superposition of being sent to box B and box C. Furthermore, causal boxes can model systems whose behavior depends on time. By instantiating the Abstract Cryptography framework with causal boxes, we obtain the first composable security framework that can handle arbitrary quantum protocols and relativistic protocols.Comment: 44+24 pages, 16 figures. v3: minor edits based on referee comments, matches published version up to layout. v2: definition of causality weakened, new reference

Toward an Algebraic Theory of Systems

We propose the concept of a system algebra with a parallel composition operation and an interface connection operation, and formalize composition-order invariance, which postulates that the order of composing and connecting systems is irrelevant, a generalized form of associativity. Composition-order invariance explicitly captures a common property that is implicit in any context where one can draw a figure (hiding the drawing order) of several connected systems, which appears in many scientific contexts. This abstract algebra captures settings where one is interested in the behavior of a composed system in an environment and wants to abstract away anything internal not relevant for the behavior. This may include physical systems, electronic circuits, or interacting distributed systems. One specific such setting, of special interest in computer science, are functional system algebras, which capture, in the most general sense, any type of system that takes inputs and produces outputs depending on the inputs, and where the output of a system can be the input to another system. The behavior of such a system is uniquely determined by the function mapping inputs to outputs. We consider several instantiations of this very general concept. In particular, we show that Kahn networks form a functional system algebra and prove their composition-order invariance. Moreover, we define a functional system algebra of causal systems, characterized by the property that inputs can only influence future outputs, where an abstract partial order relation captures the notion of "later". This system algebra is also shown to be composition-order invariant and appropriate instantiations thereof allow to model and analyze systems that depend on time

Progressive poling of large area, high r33 electro-optic polymer seo100c

SEO100c, an EO-polymer, has been reported of having an r33 in excess of 100 pm/V. Experimental poling research was performed on rib waveguide modulator for device design and development. Reported is the determination of the impact that temperature and voltage have on the poling of a SEO100c waveguide device in order to maximize the r33 while avoiding damage to the device structure ensuring high yield in manufacture. The poling process is shown to have a nonlinear relationship between r33 and poling field aiding in the selection of achievable poling voltages for required r33 values. Device thermal stability is quantified and reported for the complete poling process and the impacts upon r33 . Investigation into the possible relaxation of device r33 is measured over an extended period demonstrating desirable use within deployable devices

Maintaining a Cybersecurity Curriculum: Professional Certifications as Valuable Guidance

Much has been published about developing a cybersecurity curriculum for institutes of higher learning (IHL). Now that a growing number of IHLs globally offer such programs, a need exists on how to guide, maintain, and improve the relevancy of existing curricula. Just as cybersecurity professionals must hone their skills continually to keep up with a constantly shifting threat landscape, cybersecurity programs need to evolve to ensure they continue to produce knowledgeable graduates. In this regard, professional certifications in the cybersecurity industry offer an opportunity for IHLs to maintain a current curriculum. Governing bodies that manage professional certifications are highly motivated to ensure their certifications maintain their currency in the competitive marketplace. Moreover, employers who hire security professionals look for certifications in assessing a candidate’s overall credentials. This paper attempts to fill a void in the literature by exploring the use of professional certifications as helpful input to shaping and maintaining a cybersecurity curriculum. To this end, we offer a literature analysis that shows how changes made to professional certifications are applicable and relevant to maintaining a cybersecurity curriculum. We then provide a case study involving an undergraduate cybersecurity program in a mid-sized university in the United States. Before concluding, we discuss topics such as experiential learning, cybersecurity capstone courses, and the limitations to our approach. Keywords

Eggshell pigment composition covaries with phylogeny but not with life history or with nesting ecology traits of British passerines

No single hypothesis is likely to explain the diversity in eggshell coloration and patterning across birds, suggesting that eggshell appearance is most likely to have evolved to fulfill many nonexclusive functions. By controlling for nonindependent phylogenetic associations between related species, we describe this diversity using museum eggshells of 71 British breeding passerine species to examine how eggshell pigment composition and concentrations vary with phylogeny and with life-history and nesting ecology traits. Across species, concentrations of biliverdin and protoporphyrin, the two main pigments found in eggshells, were strongly and positively correlated, and both pigments strongly covaried with phylogenetic relatedness. Controlling for phylogeny, cavity-nesting species laid eggs with lower protoporphyrin concentrations in the shell, while higher biliverdin concentrations were associated with thicker eggshells for species of all nest types. Overall, these relationships between eggshell pigment concentrations and the biology of passerines are similar to those previously found in nonpasserine eggs, and imply that phylogenetic dependence must be considered across the class in further explanations of the functional significance of avian eggshell coloration

Unifying Generic Group Models

To prove computational complexity lower bounds in cryp- tography, one often resorts to so-called generic models of computation. For example, a generic algorithm for the discrete logarithm is one which works independently from the group representation—and thus works generically for all group representations. There are a multitude of different models in the literature making comparing different results—and even matching lower and upper bounds proven in different models— rather difficult. In this work we view a model as a set of games with the same type of interactions. Using a standard notion of reduction between two games, we establish a hierarchy between models. Different models may now be classified as weaker and stronger if a reduction between them exists. We propose different extensions of the generic group model with different queries, explicitly capturing different information that an algorithm may need to exploit. Finally, we use the hierarchy between these models to systematically compare and improve the results in the literature. First we strengthen the model in which the baby-step giant-step algorithm is proven and weaken the model in which the matching lower bound is proven. We then analyse the discrete logarithm with preprocessing. Upper and lower bounds have been proven in the literature in mismatching models. We weaken the model of the lower bound and strengthen the model of the upper bound to close the gap between the two

Giving an Adversary Guarantees (Or: How to Model Designated Verifier Signatures in a Composable Framework)

When defining a security notion, one typically specifies what dishonest parties cannot achieve. For example, communication is confidential if a third party cannot learn anything about the messages being transmitted, and it is authentic if a third party cannot impersonate the real (honest) sender. For certain applications, however, security crucially relies on giving dishonest parties certain capabilities. As an example, in Designated Verifier Signature (DVS) schemes, one captures that only the designated verifier can be convinced of the authenticity of a message by guaranteeing that any dishonest party can forge signatures which look indistinguishable (to a third party) from original ones created by the sender. However, composable frameworks cannot typically model such guarantees as they are only designed to bound what a dishonest party can do. In this paper we show how to model such guarantees---that dishonest parties must have some capability---in the Constructive Cryptography framework (Maurer and Renner, ICS 2011). More concretely, we give the first composable security definitions for Multi-Designated Verifier Signature (MDVS) schemes---a generalization of DVS schemes. The ideal world is defined as the intersection of two worlds. The first captures authenticity in the usual way. The second provides the guarantee that a dishonest party can forge signatures. By taking the intersection we have an ideal world with the desired properties. We also compare our composable definitions to existing security notions for MDVS schemes from the literature. We find that only recently, 23 years after the introduction of MDVS schemes, sufficiently strong security notions were introduced capturing the security of MDVS schemes (Damg{\r a}rd et al., TCC 2020). As we prove, however, these notions are still strictly stronger than necessary

Multi-Designated Receiver Signed Public Key Encryption

This paper introduces a new type of public-key encryption scheme, called Multi-Designated Receiver Signed Public Key Encryption (MDRS-PKE), which allows a sender to select a set of designated receivers and both encrypt and sign a message that only these receivers will be able to read and authenticate (confidentiality and authenticity). An MDRS-PKE scheme provides several additional security properties which allow for a fundamentally new type of communication not considered before. Namely, it satisfies consistency---a dishonest sender cannot make different receivers receive different messages---off-the-record---a dishonest receiver cannot convince a third party of what message was sent (e.g., by selling their secret key), because dishonest receivers have the ability to forge signatures---and anonymity---parties that are not in the set of designated receivers cannot identify who the sender and designated receivers are. We give a construction of an MDRS-PKE scheme from standard assumptions. At the core of our construction lies yet another new type of public-key encryption scheme, which is of independent interest: Public Key Encryption for Broadcast (PKEBC) which provides all the security guarantees of MDRS-PKE schemes, except authenticity. We note that MDRS-PKE schemes give strictly more guarantees than Multi-Designated Verifier Signatures (MDVS) schemes with privacy of identities. This in particular means that our MDRS-PKE construction yields the first MDVS scheme with privacy of identities from standard assumptions. The only prior construction of such schemes was based on Verifiable Functional Encryption for general circuits (Damgård et al., TCC \u2720)